Automatic control for deicing mechanism



Dec. 5, 1939. f H. BAER AUTOMATIC CONTROL FOR DICING MECHANISM Filed July 24, 197 2 Sheets-Sheet l l INVENTOR.

Howard aer BY lDec. 5,1939. H.' BAER l 2,182,530

AUTOMATIC CONTROL FOR DEiCING MECHANISM 4 Filed July 24, 1957 I 2 sheetshsheet 2 gli- lNvgNoR. Hon/aro( .Baer

Patented Dec. 5, 1939 OFI-"1C fi;

AUTOMATIC CONTROL FOR DEICIN IVIECHANISM Howard Baer, Jersey City, N. .1., assigner to Eclipse Aviation Corporation, East Orange, N.' J., a corporation of New Jersey Application July 24, 1937, Serial No. 155,550

9 Claims. k(Gi. 244-134) This invention relates to airplanes, and more particularly to a means for preventing the accumulation of ice on airplanes, particularly on the wing and tail structures.

It is Well known that under certain conditions of temperature and relative humidity, ice will form on the structural parts of an airplane. This formation is cumulative and at times seriously interferes with the control and operation of the plane. The more common locations for the ice formation are the leading edges of the wings and tail structures.

In Patent No. 1,990,866 granted to David Gregg on February 12, 1935, there is illustrated a type of flexible and expansible overshoe provided upon such leading edges of the wings and tail structures and adapted to expand and contract periodically in response to the operation of pneumatic energizing means.

An object of the present invention is to provide for the automatic initiation of the operation of such overshoe actuating means, so as tol relieve the operator of the craft of the necessity of vigilance to determine the proper moment for bringing such mechanism into operation.

Other objects of the invention will become apparent upon examination of the following description which is to be read in connection with the accompanying drawings illustrating the preferred embodiment of the invention.

In the said drawings:

Fig. 1 is a plan view of a portion of an aircraft, showing, more or less diagrammatically, one arrangement of elements embodying the novel combination of the present invention;

Fig. 2 is a detailed sectional view of the electromagnetic controller for the overshoe actuating means;

Fig. 3 is a vertical section of one of the devices for controlling energization of the electromagnetic means of Fig. 2;

Fig. 4 is a part sectional and part elevation view of the motor driven fluid distributor;

Fig. 5 is a top plan view of the distributor;

Fig. 6 is a plan view of the thermostat, used in conjunction with a humidostat, as a second means for controlling energization of the electromagnetic means; and

Fig. 7 is a side elevation of the thermostat.

Referring to the drawings and more particularly to Fig. 1, there is shown, in plan view, a portion of an airplane 4 having wings 5 and 6 provided with ice overshoes 1 and 8 at the leading edges thereof. Air under pressure for inflating the air cells or overshoes 1 and 8 is preferably derived from an engine driven pump 9 driven v by the engine I6. Each of the shoes used may be provided with a separate pipe for supplying the air thereto from the pump 9 but, in the form i1- lustrated, a distributor ll is employed which is 5 connected to the pump 9 through an oil separator l2 by means of pipe connections I3, It and l5 and is provided with three outlets I1, I6 and I8, the outlets I6 and l1 being connected to the overshoes 1 and 8 `on the wings 5 and 6 and the 10 outlet IB being connected to an overshoe or overshoes provided on the leading edgesv of the tail structure (not shown) of the airplane.

The distributor, best shown in Fig. 4, and generally designated by reference character Il con- 15 sists of a motor 14 and distributor valve 16 enclosed in a suitable housing 11, the distributor valve 16 being driven by a gear reduction unit in the form of a pair of worm and gear sets 11 and 18, the worm and gear shaft 19 being journaled 20 in bosses 8l and 82 formed in the integral extension 15of the upper portion 83 of the motor housing, said housing extension being in turn provided with a plane annular surface4 to receive and support the distributor valve housing 11, 26 with the aid of through screws 84. The distributor rotor or Valve 16 has a tongue and groove connection 86 with the Worm gear shaft 81 to be rotated thereby. The outlet pipes I6, I1, I8 and 26 are threadedly retained in radial bosses 30 on the housing 11, while the inlet pipe I3 is similarly retained in the cover plate 88. t

The motor 14 of the distributor Il is energized from a suitable source of electrical energy such as a battery I9 when the manually operated 35 switch 20 is closed. The negative side of the battery is grounded at 2| and the positive side is connected through the switch 20 to one side of the distributor -motor and the other side of the distributor motor is connected through a winding 46 22 of a solenoid valve 2.3, the purpose of which will appear hereinafter, and through a signal device such as a lamp 24 which is in parallel with the -winding 22. The circuit of winding 22 and lamp 24 is completed to ground through one of 45 two paths, namely, a humidostat andthermostat in series, or an automatic switch, all of which Will be described hereinafter.

In operation, pump 9 drives air under pressure to the distributor Il from which it is supplied in sequence, rst to overshoe 8 then to overshoe 1, and then to the overshoe or overshoes on the-tail structure, and is exhausted to the atmosphere by means of an exhaust pipe 26 55 and, hence, to the overshoes or de-icers.

all in the manner shown and described in the afore-mentioned Patent No. 1,990,866.

Means are now provided for automatically controlling the de-icing mechanism whereby the latter is automatically rendered operative when ice forming conditions begin to exist or ice begins to form on the surfaces of the aircraft. In the form shown the former means include the solenoid valve 23 and a device responsive to ice forming conditions consisting of a humidostat 89 of any conventional design, such as that illustrated in Patent No. 1,998,340 to Robert J. Streb et al., dated April 16, 1935, and a thermostat 9| likewise of modifled conventional design, such as that illustrated in Patent No. 2,060,427 to Arthur S. Robinson dated November 10, 1936. The latter means also include the solenoid valve 23 and a device 21 responsive to ice formation, both of these devices being mounted on the wingso that said devices are in the path of the slip stream. These devices include automatic switches 92 and 93 in, the case of the former and 28 in the case of the latter, all of which are normally open but automatically closed in a manner to be described later, when ice conditions occur or ice formation exists whereby solenoid valve 23 is actuated to closed position. Normally the pump 9 exhausts directly to the atmosphere by means of an exhaust 29, said pump 9 being connected to the solenoid valve 23 by means of a pipe 30. Therefore, one side of the automatic switches 93 and 28 are connected to the grounds 99 and 3| and the other side are connected to the winding 22 of the solenoid valve 23 as hereinbefore stated.

The solenoid valve shown in detail section in Fig. 2 is disclosed and claimed in my copending application Serial No. 54,487 filed December 14, 1935 and which has now matured into Patent No. 2,165,198, dated July 11, 1939, and comprises a housing 32 provided with a lateral passage 33 therethrough having an inlet 34 being connected to the pump 9 by means of the pipe 30 and the outlet 35 being connected to the exhaust pipe 29 as shown in Fig. 1. 'I'he passage 33 is adapted to be closed by means of a valve member 36 which is adapted to be moved into the seat 31 against the pull of the coil spring 38, one end of which is secured to an adjustable nut 39 threaded in an extension 40 of the housing 32, and the other end of said spring secured to the end of the valve stem 4| of the valve member 36. The valve stem 4| is of magnetic material such as soft iron and constitutes a plunger of the solenoid formed by coil 22 which is wound on a sleeve 42 through which the plunger 4| extends. The ends of the coil 22 are connected to the terminal binding posts 43 and 44 by means of which the coil 22 is connected to the device 21 and to the battery I9 through the distributor Il.

Normally, the passage 33 is open, as shown, with the valve member 36 suspended from the spring 38, so that the pump 9 is connected to the atmosphere through said passage 33 and exhaust pipe 29, whereby the pump is ineil'ective to supply air pressure to the distributor Il When the automatic switches 92 and 93 and/or switch 28 of the devices 89, 9| and 21 respectively are closed, however, the coil or winding 22 becomes energized thereby operating the plunger 4| by a downward magnetic pull against the pull of the spring 38, thus closing the passage 33, Where- 75 by the pump is then' effective to supply all t0 the overshoes through the distributor which, as previously stated, inflates the shoes in a cyclic sequence in a manner described and claimed in the aforesaid patent No. 1,990,866 whereby when one overshoe is inflated the second overshoe is partially inflated and the third overshoe is deflated, each overshoe becoming inated in turn.

A by-pass 45 is provided which communicates with the passage 33 on opposite sides of the valve seat 31. 'I'he by-pass 45 is normally closed by means of the valve member 46 which is held in closed position by means of a coil spring 41 one end of which abuts `the valve member 46 and the other end of which abuts an adjustable nut 48 which is provided for regulating the pressure at which the valve 46 may automatically open. The valve 46 constitutes a relief valve for releasing the air to the atmosphere when the pressure in the pump exceeds a predetermined limit determined by the adjustment of the spring 41 and when the valve member 36 is in closed position, i. e., when the de-icing mechanism is operating.

The automatic control device which is responsive to ice formation is shown in sectional detail in Fig. 3 and comprises a streamlined tubular member 49 which merges into a separate streamlined compartment 50 formed by a tapered end 5| and a blunt front end 52 facing the di. rection of travel of the airplane, and also by side walls (not shown). The device is carried by a streamlined mounting bracket 53 by means of which said device may be mounted on the wing of the airplane as shown in Fig. l, so that when the aircraft is in flight, air enters at the left end of the tubular member 49, as viewed in Fig. 3, passes therethrough and out of said member.

Within the tubular member 49 and in the path of the air passing therethrough there is provided a member in the form of a paddlehaving a circular portion 54 and an integral arm 55 which projects into a slot 56 providedin the bottom wall of the tubular member 49 and into the compartment 50. The arm 55 is pivoted on a shaft 51 the ends of which are secured in the side walls of the compartment 50 so that as air rushes through the tubular member 49 the circular portion 54 of the 4paddle is moved in the direction of the arrow shown in Fig. 3 against the compression of a coil spring 58 one end of which abuts the end 59 of the paddle arm 55 and the other end of which is fastened to a screw 60 in the front wall 52 of the auxiliary compartment 50. On the opposite side of the paddle arm 55 there is `provided a contact finger 6| carrying a contact 62 which is adapted to cooperate with a relatively fixed or stationary contact 63 carried by an adjusting screw 64 secured in and passing through the rear end 5I and insulated therefrom by means of an insulating bushing 65.

The contact 63 is connected to a wire 66 by means of a terminal lug secured to the adjusting screw 64 by means of a nut 61. Contact 62 is grounded by virtue of its connection to the finger 6| and arm 55 which for this purpose are made of metal as is the shaft 51 and the tubular member 49 and the mounting bracket 53. If, however, the mounting bracket 53 cannot be mounted on a grounded portion of the aircraft then the grounded connection is provided by means of a` the other end of the wire 89 is connected to the ground 3| as in Fig. 1.

The coil spring 58 tends to urge the end 59 of the arm 55 to the right as viewed in Fig. 3 to cause the contact 62 to engage contactl 63 thereby tending to close the circuit to the winding 22 of the solenoid valve 23 and to the signal lamp 24 when the manually operated switch 20 is closed. Normally, however, when the device is mounted on the wing of the aircraft, as shown in Fig. 1, the rush of air through the tubular number 49 urges the circular portion 54 of the paddle in the direction of the arrow, as shown in Fig. 3 against the compression of the spring 50 thereby maintaining the contacts 02 and 53 normally open. Thus the contacts 62 and 63 constitute the automatic switch 28 referred to hereinbefore and shown generally in Fig. 1.

Means are now provided whereby the rush of air through the tubular member 49 is prevented when ice formation takes place and, as illustrated, said means comprises a fine wire mesh screen 1| placed over the front end of the tubular member 49, said screen being securely held in place by means of a clamping ring 12 secured to the tubular member 49 in any suitable manner as by means of screws 13. Thus, as sleet and/or ice form on the screen 1I, the passage through the tubular member 49 become blocked either partially or entirely whereby the air pressure on the circular portion 54 of the paddle is reduced or eliminated so that spring 58 urges the contact 62 into engagement with the contact 63 to close the electrical circuit to the winding 22 and signal lamp 24, thereby giving a warning signal and automatically starting the de-icing mechanism in operation.

The additional novel control device which may be used in conjunction with or without the device 21 and responsive to ice forming conditions consists primarily of a shunt circuit 90 including thermostat 9| and humidostat 89, as hereinbefore stated. The thermostat as best viewed in Figs. 6 and 7 comprises a metallic base |0I upon which is mounted an arcuate contact strip |02 insulated therefrom as by fibre portion |03, the contact strip |02 terminating in binding post |04 to which the wire from the humidostat 89 may be attached. Cooperating with the contact strip to constitute the automatic switch previously referred to is a lip |06 of a conducting arm |01, pivotaily mounted as at |08 to the base IOI, and controlled by a bimetal spring |09, one end of which is fixed in the pivot post |08 and the other end of which is anchored to the base |I as by post I I 0. The relationship between contact strip |02 and lip |06 of switch arm |01 at the time of closing is under the control of bimetal spring I 09,

and so established that the time of closing will occur at approximately 32-34 Fahrenheit. The whole assembly is mounted on the metal framework of the wing as by screws (not shown) inserted in holes |II of the base IOI.

The other unit, namely the humidostat above referred to and shown in Patent 1,998,340, is connected in series with the thermostat by means of terminals 92 and ||2 corresponding to .terminals 45 and 3| respectively of the patent, the circuit between these two terminals being closed by the automatic switching means I8 and 20, the operation of which is more fully described in detail in the Gregg patent above identified.

The operation of this shunt circuit 90, is based upon the known fact that the formation of ice or snow is governed by two factors, namely, temperature and humidity. when the requisite freezing temperature occurs with an attendant moisture saturation suiiicient to induce snow or ice forming conditions, a shunt path for current ow independent of unit 21 will be established from the source I9 through switch 20 to motor I4 and solenoid 22, lead 90, humidostat 88 and thermostat 9| in series, thence returning to the source by way of the grounded path 99 and 2|.

Thus the overshoe actuating means will be energized even in advance of actuation, by ice formation, of the unit 21, so that the latter unit becomes unnecessary, except as an emergency supplement, or secondary safeguard, to insure operation of the de-icing mechanism, to periodically inflate and deflate the overshoes, which as previously stated, are of rubber fabric so that the stretch of the fabric breaks the ice which is then carried away by the air'stream.

The signal lamp 24 is preferably mounted on the instrument panel (not shown) of the aircraft so that the pilot may readily observe the same when a signal is given. The signal lamp, however, is not necessary to the operation of the deicing mechanism.

There is thus provided a novel combination including a de-icing mechanism and a device or devices exposed to the atmosphere for automatically operating said de-icing mechanism when ice forming conditions exist and ice begins to form on the wings of the aircraft, whereby accumulation of ice on said wings is substantially eliminated and/or prevented.l

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is, therefore, to be had to the appended claims for a definltion of the limits of the invention.

What is claimed is:

1. In an aircraft, de-icing mechanism for preventing ice accumulation on the exterior surface of said aircraft and for removing such ice as may have formed on said surface, and means responsive to the presence of the slightest trace of moisture in the air at freezing temperatures and to the ice formation resulting therefrom for automatically controlling said de-icing mechanism.

2. In an aircraft, de-icing mechanism for preventing ice accumulation on the exterior surface of said aircraft and for removing such ice as may have formed on said surface, means responsive to the presence of the slightest trace of moisture in the air at freezing temperatures and to the ice formation resulting therefrom for rendering said de-icing mechanism operative, and means electrically associated with said ice responsive means for energizing said de-icing mechanism whenever ice forming conditions appear.

3. In an aircraft, de-icing mechanism for preventing ice accumulation on the exterior surface of said aircraft and for removing such ice as may have formed on said surface, means responsive to the presence of the slightest trace of moisture in the air at freezing temperatures and to the ice formation resulting therefrom for automatically controlling said de-icing mechanism, and means electrically associated with said ice responsive means for energizing said de-icing mechanism whenever ice forming conditions appear.

4. In combination, an aircraft, de-icing mechanism including intlatable members on the surface of said aircraft for preventing accumulation of ice on said surface, means for periodically intlating said inflatable members, means on said surface and responsive to ice formation for automatically controlling said inating means, and means electrically associated with said ice responsive means for energizing said de-icing mechanism whenever ice forming conditions appear.

5. In combination with an airplane, a source of fluid pressure, a plurality of expansible members secured to the plane structure, means for periodically connecting the members with said source, means responsive to ice formation on said plane structure for automatically controlling said connecting means, and means electrically assosiated with said ice responsive means for energizing said de-icing mechanism whenever ice forming conditions appear.

6. In combination with an airplane, a source of uid pressure, a plurality of expansible members secured to the plane structure, means including a distributor valve for periodically connecting the members with said source, means responsive to ice` formation on said plane structure for automatically controlling said connecting means, and means electrically associated with said ice responsive means for energizing said de-icing mechanism Whenever ice forming conditions appear.

7. In combination with an airplane, a source of uid pressure, a plurality `of expansible members secured to the plane structure, means for periodically connecting said members with said source, means on said plane structure responsive to ice formation on said structure for automatically controlling said connecting means, and means electrically associated with said ice responsive means for energizing said de-icin mechanism whenever ice forming conditions appear.

8. In combination with an airplane having an engine driven jpump, a plurality of expansible members secured to the plane structure, a distributor valve for supplying iluid under pressure from said pump to said expansible members, means normally rendering said pump ineffective to supply uid under pressure, means responsive to ice formation on said plane structure for automatically actuating said last named means whereby said pump is rendered effective to supply fluid under pressure to said expansible members through said distributor valve, and means electrically associated with said ice responsive means for energizing said de-icing mechanism whenever ice forming conditions appear.

9. In combination with an airplane, a plurality `of expansible members connected to the plane structure, an air pump, means for driving said pump, an electrically operated rotary distributor valve for connecting said pump to said expansible members, a solenoid valve normally rendering said pump ineffective to pumpair to said distributor valve, an electric circuit including said rotary distributor, said solenoid valve and a source of electric current, means responsive to ice formation on said plane structure for rendering said circuit effective to cause actuation of said -rotary distributor and solenoid valve whereby said pump supplies air under pressure to said expansible members through said distributor, and motor driven speed reducing means for driving said distributor valve.

HOWARD BAER. 

